Seaweeds form extensive habitats in British coastal waters
This month’s Editor’s Choice from the Journal of the Marine Biological Association is entitled The distribution and environmental requirements of large brown seaweeds in the British Isles. In this blog two of the author’s, Chris Yesson from the Zoological Society of London and Juliet Brodie from the Natural History Museum, discuss the significance of the study.
“If you go down onto the rocky seashore you will notice that it is defined by large brown seaweeds. Delve a little deeper and you enter the realm of the kelp forest. These habitat-forming species create some of the most productive ecosystems on earth, and they are an important source of food, as well as having a diverse range of uses in the medical, pharmaceutical and chemical industries and as biofuels.
Anecdotal reports suggest that, in some areas, these species are declining, possibly induced by human pressures, including climate change. At the same time, there is increasing interest in the wild harvesting of these seaweeds and in their use in aquaculture. Despite this interest, we know relatively little about the distribution of these seaweeds and how the environment affects them. In comparison to other parts of the world, very little research has been undertaken on brown seaweeds in the UK.
The Northeast Atlantic is a hotspot for seaweed diversity, and Britain is a goldilocks zone for these large brown varieties. The British Isles is ‘just right’ climatically, being neither too hot nor too cold for most species and it lays at the centre of their distribution in the NE Atlantic.
Our study collated over 127,000 observations from a wide variety of museum collections and surveys. We examined the distribution of 15 species of kelp and wracks, including Bladder Wrack (Fucus vesiculosus), serrated wrack (Fucus serratus), Sugar Kelp (Saccharina latissima), along with the invasive species Wireweed (Sargassum muticum), and the range expanding Golden Kelp (Laminaria ochroleuca).
We mapped the distribution of these species and examined associated environmental conditions. We made a model to estimate the potential distribution of each species throughout the British Isles. Our results revealed that attachment sites (e.g. rocks or other hard surfaces) and shelter/exposure are the most important factors. Temperature does not appear to limit most of these species in Britain which has important implications for their potential resilience to predicted climate change.
We estimate that kelp habitats cover 19,000 km2, and wracks cover 11,000 km2. This compares favourably with native broadleaf woodland estimated to cover around 10,000 km2.
Our results confirm the importance of these seaweeds as habitat creators. Given the extent of these habitats, it is clear that they require a similar level of attention and conservation management as for terrestrial ecosystems.”